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A copper/air-gap interconnection structure using a sacrificial polymer and SiO/sub 2/ in a damascene process has been demonstrated. The air-gap occupies the entire intralevel volume with fully densified SiO/sub 2/ as the planar interlevel dielectric. The copper was deposited by physical vapor deposition and planarized by chemical-mechanical planarization. The Ta/Cu barrier/seed layer was deposited by physical vapor deposition; the bulk copper was electrochemically deposited. The resulting structure has an effective intralevel dielectric constant of 2.19.

Four-dimensional imaging is a necessary step in computer-assisted interventions (CAI) performed on moving surgical targets, such as those located within the beating heart or influenced by respiratory motion. Ultrasound (US) is often the best imaging modality for this application, as it provides good contrast and spatial resolution while remaining simple to integrate into the operating room. However, conventional 2D US imaging is often insufficient for preoperative planning and surgical guidance, real-time 3D ultrasound imaging using matrix array probes has a smaller field of view and lower spatial resolution, and 3D volumes created using 3D US reconstruction suffer from motion artifacts. As an alternative, gated 4D ultrasound reconstruction using a tracked 2D US probe is a promising technology. In this paper, we present SynchroGrab4D to the open-source community. SynchroGrab4D performs 3D and 4D US reconstruction in real-time while visualizing the output volume(s) within an OpenIGTLink-compliant CAI system, such as 3D Slicer. Also included are VTK classes that perform ECG-gating and that interface with several commercial tracking systems, as well as a 4D Imaging module in 3D Slicer. Our open-source imaging system can be used to collect the 4D image data required for computer-assisted surgical planning and intraoperative guidance for a variety of moving organs.

Background: Commercially available bile-acid sequestrants are not well tolerated by >80% of patients. Objective: The aim of the present study was to assess the effectiveness and tolerability of colesevelam hydrochloride in patients who developed bile-acid malabsorption after cancer therapy. Methods: The present study comprised 2 parts: a retrospective chart review of the electronic patient records and a patient questionnaire assessing outcome measures. All patients included in this study had a diagnosis of cancer and were being followed up in a cancer clinic at The Royal Marsden Hospital. In addition, all had symptoms of bile-acid malabsorption for >3 months and had been prescribed colesevelam in the gastroenterology clinic at the hospital. The electronic records of patients who were prescribed colesevelam between 2004 and 2007 were obtained from the hospital pharmacy. Those patients who were prescribed colesevelam and did not take any of the prescribed medication or did not return for a follow-up clinical review were excluded. To help further assess outcomes, a questionnaire was mailed to patients who were still residing in the United Kingdom, were not terminally ill, and were not lost to follow-up. The questionnaire comprised questions that assessed medication history (ie, whether patients were still taking colesevelam or not [and the reason for not taking colesevelam]), dosage, effectiveness for symptom relief, and adverse events. Results: In total, 45 patients (37 women and 8 men; median age, 58 years [range, 32–89 years]) who received treatment with colesevelam between 2004 and 2007 were included. Of these, 36 were sent a questionnaire and 30 responded. Identifiable causes of bile acid malabsorption in this sample population were pelvic radiotherapy (n = 29), small-bowel resection (12), upper gastrointestinal surgery (2), high-dose chemotherapy (1), and new-onset Crohn's disease (1). Of these patients, 67% (30/45) had not previously responded to cholestyramine treatment, but following treatment with colesevelam, this group had a recorded improvement in: diarrhea, 83% (25/30); urgency of defecation, 74% (20/27); frequency of defecation, 72% (21/29); steatorrhea, 71% (12/17); abdominal pain, 68% (15/22); and fecal incontinence, 62% (13/21). Based on the medical chart review and the patient questionnaire, after colesevelam treatment, the following proportions of all 45 patients studied experienced improvement in symptoms: loose stool (diarrhea), 88% (medical chart) and 80% (questionnaire); frequency of defecation, 77% and 83%, respectively; steatorrhea, 76% and 80%; urgency of defecation, 76% and 80%; abdominal pain, 74% and 58%; and fecal incontinence, 69% and 74%. During the study period, 15 patients discontinued colesevelam: ineffectiveness, 5; adverse events, 5 (because ≥1 of the following: bloating, constipation, heartburn, abdominal pain, flatulence, or perianal soreness); and other reasons, 7 (too many tablets or tablets difficult to swallow [3]; symptoms resolved [2]; colesevelam replaced with another medication [1]; and lost to follow-up [1]). Sixty-seven percent (30/45) of patients continued using colesevelam for up to 4 years. Conclusion: In view of the data found in this retrospective chart review and patient questionnaire, prospective, double-blind, placebo-controlled trials of colesevelam for bile acid malabsorption are warranted.

Surgeon-to-computer interaction difficulties in using virtual reality (VR)-guided surgical environments arise from disorientation, insufficient depth information, and delegation of view control. This study focuses on optimizing information delivery for VR-guided beating heart surgery. Initial human factors evaluation and participatory design has provided insight for developing an effective surgeon-controlled interface for VR-guided cardiac interventions. We discuss the motivation for and development of three interface prototypes as well as the methodology used to measure the effect of these novel techniques on user performance and workload.

[ES] Este es un examen de la estrangulación carotídea, también conocida como la “presa durmiente”. Nos preocuparemos de los tipos de agarres durmientes y de qué parte del cuello se ve afectada y cómo. Se denomina habitualmente “estrangulación sanguínea”. Existe una diferenciación entre las estrangulaciones sanguíneas y las estrangulaciones respiratorias. Este artículo tratará la aplicación, efectos, resultados a corto y largo plazo, y ramificaciones respecto a la utilización de drogas y al estado men-tal. No incluiremos los efectos de una estrangulación sobre la traquea, o de la presión o los golpes a la parte posterior del cuello. Este artículo se presenta desde dos perspectivas; la del practicante/instructor de artes marciales y la del médico.

Detailed heat transfer and aerodynamic measurements have been made on an annular cascade of highly loaded nozzle guide vanes. The tests were carried out in an Isentropic Light Piston test facility at engine representative Reynolds number, Mach number and gas-to-wall temperature ratio. The aerodynamics indicate that the vane has a weak shock at 65–70% axial chord (mid span) with a peak Mach number of 1.14. The influence of Reynolds number and Mach number on the Nusselt number distributions on the vane and endwall surfaces are shown to be significant. Computational techniques are used for the interpretation of test data.

In an effort to reduce morbidity of cardiac interventions, minimizing invasiveness inevitably leads to limited visual access to the surgical targets. To address these limitations, we provide the surgeons with a robust visualization environment that integrates interventional ultrasound imaging augmented with pre-operative anatomical models and virtual surgical instruments within a virtual reality environment. Here we present an in vitro study on a cardiac phantom that mimics an ablation therapy procedure, which allows us to assess the feasibility of our surgical system in comparison to traditional intra-operative ultrasound imaging. Following surgical target identification via an electro-anatomical model, the "ablation procedure" is performed blindly. A 2.8 mm RMS targeting error is achieved using our novel surgical system. This level of accuracy is adequate from both a clinical and engineering perspective, under the inherent procedure requirements and limitations of the system.

Minimally invasive techniques for electrophysiological cardiac data mapping and catheter ablation therapy have been driven through advancements in computer-aided technologies, including magnetic tracking systems, and virtual and augmented-reality environments. The objective of this work is to extend current cardiac mapping techniques to collect and display data in the temporal domain, while mapping on patient-specific cardiac models. This paper details novel approaches to collecting spatially tracked cardiac electrograms, registering the data with a patient-specific cardiac model, and interpreting the data directly on the model surface, with the goal of giving a more comprehensive cardiac mapping system in comparison to current systems. To validate the system, laboratory studies were conducted to assess the accuracy of navigating to both physical and virtual landmarks. Subsequent to the laboratory studies, an in-vivo porcine experiment was conducted to assess the systems overall ability to collect spatial tracked electrophysiological data, and map directly onto a cardiac model. The results from these experiments show the new dynamic cardiac mapping system was able to maintain high accuracy of locating physical and virtual landmarks, while creating a dynamic cardiac map displayed on a dynamic cardiac surface model.

In the context of our ongoing objective to reduce morbidity associated with cardiac interventions, minimizing invasiveness has inevitably led to more limited visual access to the target tissues. To ameliorate these challenges, we provide the surgeons with a complex visualization environment that integrates interventional ultrasound imaging augmented with pre-operative anatomical models and virtual surgical instruments within a virtual reality environment. In this paper we present an in vitro study on a cardiac phantom aimed at assessing the feasibility and targeting accuracy of our surgical system in comparison to traditional ultrasound imaging for intra-operative surgical guidance. The 'therapy delivery' was modeled in the context of a blinded procedure, mimicking a closed-chest intervention. Four users navigated a tracked pointer to a target, under guidance provide by either US imaging or virtual reality-enhanced ultrasound. A 2.8 mm RMS targeting error was achieved using our novel surgical system, which is adequate from both a clinical and engineering perspective, under the inherent procedure requirements and limitations of the system.

Reliable, non-invasive biological markers of the severity of radiotherapy-induced damage to the gastrointestinal tract are not available. Clinicians continue to use symptom scores as surrogate indicators of toxicity.To determine whether levels of potential biochemical markers of mucosal toxicity change during pelvic radiotherapy.Fifty-nine patients (30:29 males:females) with mixed pelvic malignancies, receiving 45-70 Gy were recruited. At baseline and weeks 4 or 5 of radiotherapy, blood samples for citrulline, C-reactive protein, eosinophil cationic protein and stool samples for faecal calprotectin were obtained. Symptoms were measured using the Inflammatory Bowel Disease Questionnaire - Bowel Subset, Radiation Therapy Oncology Group and Vaizey Incontinence Questionnaires. Paired t-tests of change in marker values were calculated.Citrulline (P = 0.02) and faecal calprotectin (P = 0.01) values changed significantly between baseline and 4/5 weeks. Inflammatory Bowel Disease Questionnaire - Bowel Subset fell significantly (mean fall = 10 points, s.d.: 8.9). Changes in markers did not correlate with symptoms.Some biochemical markers of mucosal toxicity change significantly during treatment. Further studies must investigate the timing of changes of these biochemical markers, their relationship to gastrointestinal physiological change and the radiotherapy dose delivered to the gastrointestinal tract and whether changes in markers acutely can predict the degree of long-term gastrointestinal dysfunction.

Cardiopulmonary bypass surgery, although a highly invasive interventional approach leading to numerous complications, is still the most common therapy option for treating many forms of cardiac disease. We are currently engaged in a project designed to replace many bypass surgeries with less traumatic, minimally invasive intracardiac therapies. This project combines real-time intra-operative echocardiography with a virtual reality environment providing the surgeon with a broad range of valuable information. Pre-operative images, electrophysiological data, positions of magnetically tracked surgical instruments, and dynamic surgical target representations are among the data that can be presented to the surgeon to augment intra-operative ultrasound images. This augmented reality system is applicable to procedures such as mitral valve replacement and atrial septal defect repair, as well as ablation therapies for treatment of atrial fibrillation. Our goal is to develop a robust augmented reality system that will improve the efficacy of intracardiac treatments and broaden the range of cardiac surgeries that can be performed in a minimally invasive manner. This paper provides an overview of our interventional system and specific experiments that assess its pre-clinical performance.

Background Acute gastrointestinal symptoms affect 90% of patients during pelvic radiotherapy. Elemental diet is protective in animal models. A nonrandomized study suggested benefit from a partial elemental diet. A pilot study suggested that radiotherapy patients only tolerate oral elemental diet comprising one-third of total calories for 3 weeks. Aim To assess the feasibility and efficacy of replacing one-third of normal diet with elemental diet during the first 3 weeks of pelvic radiotherapy in reducing acute gastrointestinal toxicity. Methods Patients were randomized to elemental diet or no intervention. Toxicity was assessed using the Inflammatory Bowel Disease Questionnaire, Vaizey Incontinence scale and Radiation Therapy Oncology Group tool. Faecal calprotectin measured intestinal mucosal inflammation. Results Twenty-nine women and 21 men, median age 61.5 years were randomized. Patients taking elemental diet did not have lower gastrointestinal toxicity ratings or inflammatory markers (P > 0.2). The mean dose taken was 21% (2-36%) of total caloric requirements. Conclusions Patients cannot tolerate large volumes of oral elemental diet. The quantities consumed in this study produced no therapeutic benefit. Future studies should aim to replace a higher proportion of nutritional intake for a longer duration of radiotherapy treatment.

Introduction Loose stool affects up to 80% of all patients during pelvic radiotherapy and faecal incontinence may occur. Several causes for diarrhoea have been defined, though few oncologists target these causes in affected patients and most treat symptomatically only. It is not known whether small bowel bacterial overgrowth, a frequent cause of gastrointestinal symptoms in other contexts, occurs during radiotherapy. The frequency of new-onset lactose intolerance during pelvic radiotherapy is also not clear. Aims and methods To perform an observational pilot study to estimate the incidence of small bowel bacterial overgrowth and lactose intolerance during radical pelvic radiotherapy. Before treatment started and at weeks 4–5 of pelvic radiotherapy, a glucose hydrogen breath test and lactose tolerance test were performed. Gastrointestinal symptoms were assessed using the Vaizey incontinence questionnaire and the Radiation Therapy Oncology Group scoring system. Results Twenty two men and 17 women (median age 61, range 42–81) were recruited, four were treated for gastrointestinal, 17 were treated for gynaecological and 18 for urological cancers. Thirty-eight patients underwent glucose hydrogen breath tests and 26 patients underwent lactose breath tests at both time points. Ten patients (26%) were positive for the glucose hydrogen breath test: 60% of these developed new or worsening faecal incontinence during treatment and 60% had worsening bowel frequency. Four patients (15%) developed lactose intolerance. Of these 1 developed worsening faecal incontinence during treatment, 2 (50%) developed new-onset increase in bowel frequency or a change in the quality of bowel habit. Conclusion Small bowel bacterial overgrowth and lactose intolerance may occur during radical pelvic radiotherapy and are likely to contribute to gastrointestinal symptoms in some patients.

An interventional system for minimally invasive cardiac surgery was developed for therapy delivery inside the beating heart, in absence of direct vision. A system was developed to provide a virtual reality (VR) environment that integrates pre-operative imaging, real-time intra-operative guidance using 2D trans-esophageal ultrasound, and models of the surgical tools tracked using a magnetic tracking system. Detailed 3D dynamic cardiac models were synthesized from high-resolution pre-operative MR data and registered within the intra-operative imaging environment. The feature-based registration technique was employed to fuse pre- and intra-operative data during in vivo intracardiac procedures on porcine subjects. This method was found to be suitable for in vivo applications as it relies on easily identifiable landmarks, and hence, it ensures satisfactory alignment of pre- and intra-operative anatomy in the region of interest (4.8 mm RMS alignment accuracy) within the VR environment. Our initial experience in translating this work to guide intracardiac interventions, such as mitral valve implantation and atrial septal defect repair demonstrated feasibility of the methods. Surgical guidance in the absence of direct vision and with no exposure to ionizing radiation was achieved, so our virtual environment constitutes a feasible candidate for performing various off-pump intracardiac interventions.

Many intracardiac procedures can currently be performed on the heart only after it has been arrested, and the patient has been placed on cardio-pulmonary bypass. We have developed a new method for operating on multiple targets inside the beating heart, and describe a procedure for accessing them under virtual-reality (VR)-assisted image guidance that combines real-time ultrasound with a virtual model of tools, and the surgical environment acquired from pre-operative images. This paper presents preliminary results aimed at assessing the operator's ability to accurately position and staple an artificial valve to a "valve orifice" within a cardiac phantom when guidance is performed via ultrasound alone, and with US augmented by the VR environment.

Introduction An estimated 17,000 patients a year in the UK receive radiotherapy (RT) for pelvic cancers. Acute damage to normal gastrointestinal mucosa (toxicity) is characterised by an inflammatory response that may respond to altered dietary fibre intake through a range of mechanisms. The aim was to undertake a 3-arm, randomised controlled trail comparing high fibre, low fibre, and habitual fibre diet for the prevention of radiation induced toxicity in the short (6 weeks) and long term (1 year) in patients receiving radical (≥45 Grey) RT for lower gastrointestinal or gynaecological malignancies. Method Patients were randomised to high fibre (target ≥18 g/d non-starch polysaccharide, NSP), low fibre (≤10 g/d NSP) or habitual fibre (control) groups. The primary end-point was the inter-group difference in change in Inflammatory Bowel Disease Questionnaire – Bowel Subset (IBDQ-B) score: start of RT to nadir (worst) score. Patients completed two 7-day food diaries, daily Bristol Stool Form Scale and a sub-group provided stool samples for faecal short-chain fatty acid (SCFA) analysis. Results A total of 166 patients were randomised (High: 56, Low: 55, Control: 55); median (range) age: 62.5 (26 – 91) years; males:females 42%:58%; median RT dose: 50.4 Grey; 72% concomitant chemotherapy. NSP intake was significantly different between groups at start and end-RT (p Conclusion The results show a benefit for increased fibre intake during pelvic RT. However, the findings are equivocal as the fall in IBDQ-B scores at end-RT and at one year were not significantly different between high fibre and low fibre groups. High and low fibre intake may provide benefit via different mechanisms although the possible therapeutic effect of dietary intervention alone cannot be ruled out. A high fibre diet was shown to reduce radiation-induced toxicity in patients undergoing pelvic RT. Disclosure of interest None Declared.

We present an application of an augmented reality laser projection system in which procedure-specific optimal incision sites, computed from pre-operative image acquisition, are superimposed on a patient to guide port placement in minimally invasive surgery. Tests were conducted to evaluate the fidelity of computed and measured port configurations, and to validate the accuracy with which a surgical tool-tip can be placed at an identified virtual target. A high resolution volumetric image of a thorax phantom was acquired using helical computed tomography imaging. Oriented within the thorax, a phantom organ with marked targets was visualized in a virtual environment. A graphical interface enabled marking the locations of target anatomy, and calculation of a grid of potential port locations along the intercostal rib lines. Optimal configurations of port positions and tool orientations were determined by an objective measure reflecting image-based indices of surgical dexterity, hand-eye alignment, and collision detection. Intra-operative registration of the computed virtual model and the phantom anatomy was performed using an optical tracking system. Initial trials demonstrated that computed and projected port placement provided direct access to target anatomy with an accuracy of 2 mm.

We were pleased to read that other groups are exploring the feasibility of detailed self-recording of dietary intake in patients receiving long-course radiotherapy for prostate cancer. This has particular relevance in view of the continued interest in strategies to minimise rectal deformation and thus reduce prostate movement during radiotherapy planning and treatment. We completely agree with the authors’ finding that previous studies, which have explored dietary interventions (primarily anti-flatulent diets), have lacked information on patient compliance. Thus, in the one study, which failed to show a statistically significant difference in inter-fraction prostate motion, and in the two studies, in which worse outcomes were observed in terms of increased prostate displacement, it is impossible to know whether the outcomes result from a true lack of efficacy or indeed adverse effects of the diet alone. This uncertainty is compounded by the fact that only one of the studies used dietary change as the sole intervention. The others used a combination of laxatives and diet, and laxative diet and treatment scheduling. Further, only one study used a prospective comparator group with patients acting as their own controls.

We have developed an augmented reality system capable of projecting preoperative plans directly onto a patient using rapidly scanned laser beams. Projected contours can typically represent cut paths, tumors or delineate boundaries of interest. The system can be used as part of, or a replacement for, conventional robotic Telesurgery systems. Because the graphics are projected, there is no degradation in surgeon's view due to optical components interposed between the surgeon's eye and the patient. This system has been designed to work with a common infrared 3D camera system used in image-guided surgery, and projects both visible and infrared beams. The IR beam enables surface digitization functions to be carried out using the camera. The clinical accuracy is in the range required by CAS procedures, around 1-2mm. The device will be particularly useful for executing precise preoperative plans and for teleconsultation applications, where planned or live consultations can be efficiently communicated to a less skilled local caregiver.

Recent results in the design automation of continuous-time transconductance-C filters are presented. These results are limited to grounded capacitors and are reported only for CMOS technologies. A high-level behavioral description of an LC ladder is outlined using a signal-flow graph technique. It is shown that a simple, four-line grammar provides enough versatility for several design generators to produce files for SPICE analysis and Magic layouts of the signal-flow graph simulation of the LC ladder. Areas of future work in these early stages of development of design automation of analog subsystems and circuits are suggested. >

The AirLand Battle Management (ALBM) Program is a prototype demonstration project sponsored by DARPA and the US Army. Its goal is to demonstrate that advanced computer processing and artificial intelligence techniques, particularly cooperating expert systems, can be used to accelerate and improve the development of US Army manoeuver and fire support plans for airland battle forces. The program is providing a decision support environment that helps commanders and staff officers reason about complex situations represented by large amounts of information. There are two major components, FORCES and STAR. FORCES is a collection of prototype cooperating expert systems which support the commander and staff in performing the decision-making process. STAR is a collection of computer programs (tools) which provide the foundation for FORCES, enabling developers to build additional application programs rapidly, and enabling soldiers to add new knowledge. >

NAVL (Newtonian Architecture for Virtual Landscapes) is a distributed virtual reality system designed with the goal of achieving a high degree of network efficiency; in particular, by using a hierarchical network architecture that is more efficient than traditional peer-to-peer or client-server architectures, and simulating the virtual world on the local hosts using a Newtonian based model, thereby functioning as a high order dead reckoning protocol. This paper presents the general overview of the NAVL VR system along with details of the proposed implementation.

The Newtonian Architecture for Virtual Landscapes Distributed Virtual Reality (NAVL DVR) system compensates for network lag by using a distributed execution model. This paper presents the design of the simulation and execution architecture for the NAVL DVR system. Highlights include: event driven behaviour execution routines, simulation infrastructure for evaluating paths through space-time at local display nodes, and the thread architecture for the simulation and execution architecture support.

A hybrid architecture for Hopfield artificial neural networks and its GaAs implementation are described in this paper. This approach merges parallel summation and multiplication and serial neuron state updating. For a N/spl times/N network, only N multipliers and one neuron activation function are needed.

An alternative approach to lithography is being developed based on a dual-layer imprint scheme. This process has the potential to become a high-throughput means of producing high aspect ratio, high-resolution patterns without projection optics. In this process, a template is created on a standard mask blank by using the patterned chromium as an etch mask to produce high-resolution relief images in the quartz. The etched template and a substrate that has been coated with an organic planarization layer are brought into close proximity. A low-viscosity, photopolymerizable formulation containing organosilicon precursors is introduced into the gap between the two surfaces. The template is then brought into contact with the substrate. The solution that is trapped in the relief structures of the template is photopolymerized by exposure through the backside of the quartz template. The template is separated from the substrate, leaving a UV-curved replica of the relief structure on the planarization layer. Features smaller than 60 nm in size have been reliably produced using this imprinting process. The resolution silicon polymer images are transferred through the planarization layer by anisotropic oxygen reactive ion etching. This paper provides a progress report on our efforts to evaluate the potential of this process.